The invention relates to a method for producing a cushion element or a cushion support essentially made of a cushion material, preferably a fiber composite material, in particular a cushion support for a motor vehicle seat. The cushion element comprises in particular a cushion element or a cushion support for a seat part and a cushion element or a cushion support for a backrest part in this case, wherein the cushion element covers the carrier structure of the seat made of metal or plastic to increase the seat comfort. Furthermore, the invention relates to a cushion element and a vehicle seat having a cushion element.
Over 90% of the cushion supports for seats and backrests in the furniture and automobile fields consist of polyurethane soft foam (PUR soft foam). The main reason for the above-average presence of polyurethane soft foam in cushion supports is founded in the comparatively low price of the final product. These cushion supports made of PUR foam have the disadvantage that the seat climate is comparatively poor. With the same contour and same construction, because of the reworking such as stamping and grinding, the cushion support is more costly upon the use of fibers. However, the fiber component always has the advantage of the better seat climate.
Various methods for producing such cushion supports from fiber composite material—for example, from coconut fibers and latex as the binder—for a motor vehicle seat are known from the prior art.
In the so-called rubberized fiber method, piles made of fibers and the binder latex are first laid. Blanks are stamped out of the piles, which are sprayed once again with latex and subsequently manually laid or installed in tools. Hot air heated to approximately 120° C. is conducted through the tools, so that the latex/fiber mixture dries in the tool, after which the molded and dried cushion part is removed from the tool. The cushion part must then be cut or stamped. Subsequently, the burr arising upon the cutting or upon the stamping is removed by manual grinding. The last work step is the vulcanization of the parts in an autoclave, wherein the vulcanization can also frequently occur directly after the demolding of the cushion supports. These processing steps can be switched around depending on the contour and geometry of the part. The cushion supports can then typically also be finished further, in that specific regions are laminated with foam or also with fleece. This method has the disadvantage that it is comparatively complex and costly.
A further mass production method—known under the name “FaserTec”—is distinguished in that piles do not have to be manufactured using a laying machine, but rather the fibers are scattered with the binder (e.g., latex) directly through a scattering head into tools. Through this improvement of the method, the laying process can be omitted, however, all downstream mechanical interventions such as cutting, stamping, or grinding are still indispensable individually or in combination. In the FaserTec method, the tools are typically arranged on round tables having four or five tools. The main processes of this arrangement are the scattering of the fibers and the binder in the tool and the drying procedure. The parts are subsequently cut and/or stamped, ground, and vulcanized as in the classical rubberized fiber method. This method has the disadvantage that it is comparatively complex and costly.
As a supplement to the described rubberized fiber and FaserTec methods, which are found in mass production, there are still further developments of methods which have polyester fibers as the base material. These include the so-called Neocurle method, in which polyether sulfone or polyethylene terephthalate fibers (in short: PESIPET fibers) are wetted using a binder such as PUR and subsequently the cushion part reacts completely in a tumbling tool. This procedure is very complex and costly.